End-organ damage due to autoantibodies accounts for most of the morbidity seen in several dermatological diseases; including pemphigus vulgaris, pemphigus foliaceous, bullous pemphigoid and linear IgA disease. Given that autoantibodies are the pathogenic players in these diseases, it becomes important to understand what their antigenic (Ag) targets are. Although target antigens have been described for some of these, we do not still have a clear understanding of the full spectrum of relevant autoantigens in these diseases. In yet other dermatological diseases such as discoid lupus and psoriasis, our knowledge of target autoantigens is currently a black box. The current proposal seeks to address this knowledge gap by designing a proteome array that will enable parallel testing of patients' sera for reactivity to multiple skin Ags. The specific aims are: 1. To establish and optimize "dermatoproteome' arrays as immunoassay tools, 2. To ascertain the target antigen specificities of sera from patients with bullous diseases, and 3. To ascertain the target antigen specificities of sera from patients with discoid lupus.